When an angle modulated, e.g., FM, radio wave transmitted from a transmitting antenna reaches a receiving antenna via more than one different propagation path, interference may occur between the received signals. The interference is apt to cause the received signal to have a distortion therein. In other words, the distortion (which is referred to as interference distortion hereinafter) of the received signal occurs since both a direct wave and an indirect wave, such as a reflected wave and/or a diffracted wave, are received by the same receiving antenna. The interference distortion which occurs due to the above mentioned reason is called a multipath distortion. The occurrence possibility of multipath distortion is relatively high in cities having tall buildings.
A method which has been adopted to reduce or cancel multipath distortion is to use a receiving antenna which has a sharp directivity for receiving only the direct wave or a wave which is aimed to receive. However, this method does not work effectively when many tall buildings surround a receiving point. Therefore, a compensation circuit for cancelling or reducing the distortion may be provided. Such a circuit is called a multipath distortion compensation circuit.